446 
POPULAE SCIENCE EEYIEW. 
(fig. 2). The lateral horns are shorter, and are placed so as 
to expose a lateral angle on each side ; the whole disc is more 
lengthened than in Cephalaspis, and is produced forwards into 
a snout or “ rostrum ; ” at the sides of this the orbits are 
placed, instead of being situated in the centre of the disc. 
The striations on the surface are arranged in a very beautiful 
and symmetrical manner, running parallel with the edges of 
the shield. The posterior spine is inserted into the disc as a 
distinct piece. 
Most of the specimens which are found are very imperfect, 
leaving their outer shell in the matrix from which they are 
extracted; the rostrum, too, and the lateral and posterior 
cornua are generally so concealed in the rock, as to render it 
impossible to work out the whole disc in a perfect condition. 
The specimens usually seen are in the condition represented in 
fig. 9, and hence Dr. KnePs difficulty in believing that the 
pteraspis could be a fish. If the body had come to fight we 
should have had no difficulty about the matter ; but it is only 
just lately that any signs of even the scales of Pteraspis have 
been seen. The writer went last summer to one of the 
quarries in Herefordshire in search of the remains of Cepha- 
laspis and Pteraspis. Having obtained some few specimens, 
he visited the house of one of the workmen, there to increase 
his collection of remains. “ How, sir, what do ye think that 
may be ? 33 said the quarryman, handing the specimen drawn 
in fig. 5. “ My opinion is that it is a fir-cone.” The speci- 
men was examined, and found to be nothing more nor less than 
the long-looked-for scales of Pteraspis. There could be no 
doubt of it, for a portion of the remarkably characteristic 
shell of the cephalic disc, with its three layers, was adhering 
to the scales. An exchange was soon made with the quarry- 
man for his stone, by means of the “ current coin of the 
realm,” and the disentombed scales of that ancient Pteraspis 
were comfortably packed in wool and paper. The markings 
on the scales are shown in fig. 12, where they are slightly 
magnified.* Of course no one now can doubt that Pteraspis 
was a fish, the only thing that we have to regret is that we 
know nothing of the form of its body. The cephalic disc was 
probably placed as is shown in the sketch fig. 4. Besides the 
Cephalaspis^s and Pteraspis* s heads and scales to be found in the 
cornstones of Herefordshire, there are numerous spines — such 
as is represented in fig. 14. These generally go by the name 
of “ Onchus,” but what “Onchus” is or was beyond a spine, no 
one knows. The probabilities are that these bodies belonged 
to the Pteraspis or perhaps Cephalaspis, and served to support 
* See Journal of Geological Society. 1864. 
